Dynamic ACL Brace: In Vivo Kinematics

Inclusion Criteria: * Unilateral, complete ACL (Anterior Cruciate Ligament) ruptures (must be documented by prior MRI) * No other concomitant lower extremity injuries and an uninjured contralateral limb * Acute ACL tears that will be scheduled for ACL reconstruction with Dr. Robert F. LaPrade * Minimal swelling and pain * Able and willing to perform the required study activities Exclusion Criteria: * Previous surgery or significant injury to either knee * Relevant surgery, procedure, injury, or condition in the past two years which may affect knee pain or general movement patterns on either side * Diagnosis of osteoarthritis, rheumatoid conditions, cancers, or other conditions which may affect musculoskeletal health * Women who are pregnant, or trying/planning to become pregnant during the next 10 months * Known balance or vestibular disorders * Persons with a history of significant radiation exposure, whether occupational or medical in nature (Anyone with a history of medical radiation therapy, for cancer or other conditions, is excluded from the study. Those who have an annual occupational radiation exposure greater than 25mSv may not enroll.) * Persons with a pacemaker, hearing aid, aneurysm clip or artificial heart valve, or other forms of loose metal implants * Initial MRI exclusion criteria (assessed by clinical MRI obtained as standard of care at time of ACL injury diagnosis): concomitant injury, multi-ligamentous injury, significant meniscal damage * Allergy or sensitivity to silver or latex * Adults lacking capacity to consent for themselves Post-Op Visit Exclusion Criteria * Participants who do not pass their return-to-sport test within 7-9 months of ACL-Reconstruction surgery will be excluded from the second phase of testing. * Participants who no longer pass the MRI screening at the time of Phase 2 testing (for example, who have a new loose metal implant), will be excluded from the MRI portion of the testing only.